This book provides an introduction to the world of metamaterials and metasurfaces; artificially engineered materials that can control electromagnetic waves in ways not found in nature. These materials exhibit unusual effects with applications ranging from miniaturised antennas to advanced sensors, energy harvesting, and even future communication systems.Spanning microwave, terahertz, and optical frequency regimes, the book traces the evolution of the field from fundamental concepts to recent breakthroughs. It presents fundamental theory, modelling and characterisation techniques, while highlighting both emerging applications, such as superlensing, cloaking, and sub-wavelength imaging and established uses in absorbers, sensors, antennas, and active devices.This second edition features major updates and new content including advances in reversed Čerenkov radiation-based vacuum tube research, hyperbolic metamaterials, graphene-enabled devices, biomedical applications, acoustic metamaterials and fabrication technologies for metasurfaces. Emerging directions such as reconfigurable intelligent surfaces and ultra-massive MIMO for 6G communications are also explored.Metamaterials and Metasurfaces, 2nd Edition: Foundations, trends and applications serves as both a postgraduate teaching resource and a reference for researchers seeking a solid foundation in the principles, applications and emerging trends shaping this dynamic field.